Thermal–Hydraulic Performance of Flat‐Plate Solar Collector Plant Using Different Heat‐Transfer Fluids

Abstract

The physical parameters such as density, specific heat capacity, and viscosity of the heat‐transfer fluid have an important influence on the performance of the solar collector system. If the physical parameters of heat‐transfer fluids are studied as constant physical properties, it will be difficult to reflect the influence of heat‐transfer fluids on the performance of the solar collector system. In this study, expressions are fitted for the physical parameters of heat‐transfer fluids and a coupled thermal–hydraulic performance model of the solar collector system is established. The coupled model is validated through performance‐testing experiments on the system and is used to investigate the impact of heat‐transfer fluid types and concentrations on the performance of the system under various solar radiation intensities, ambient temperatures, inlet temperatures, and flow rates. In the results, it is shown that in the case of anti‐freezing, a 50% volume concentration of ethylene glycol is more suitable for the heat‐collecting system. When selecting the heat‐transfer fluid, the heat‐transfer fluid with a lower concentration should be selected as far as possible while ensuring the freezing point. In the results of this study, a certain reference for the selection of the heat‐transfer fluid can be provided.